Abstract: A large-capacity optical router is disclosed that exchanges data traffic such as IP packets, Ethernet frames, etc., at high speed in units of optical frames. The large-capacity optical router uses an electric buffer including input ports, output ports, an add port for inputting data received from a lower IP router, a drop port for outputting data to the lower IP router, a wavelength division demultiplexing section for wavelength-division-demultiplexing wavelength signals input through the input ports and the add port, an input interface section for converting optical frames from the wavelength division demultiplexing section into electric signals, and an optical switch for performing a high-speed switching of the optical frames from the input interface section.

Abstract: A high speed optical routing apparatus and method, in which data traffic, such as an IP packet, an Ethernet frame, etc., is switched in an optical frame unit at a high speed. The apparatus is provided with a plurality of input and output ports, and with one add port for adding data received from a lower IP router, and one drop port for dropping processed data toward the lower IP router. A header wavelength dividing unit extracts the header wavelength signals from among input optical signals inputted through the input ports and the add port. The header wavelength signals contain header information on data wavelength signals contained in the input optical signals. An optical signal inputting section demultiplexes optical signals having the data signals according to the wavelength, and for dividing and inputting the wavelength-based demultiplexed data wavelength signals according to a frame.

Abstract: Disclosed is a two-fiber optical ring network having a plurality of nodes linked by first and second fiber optic links, wherein each node comprises a first splitting section for splitting optical signals from optical signals traveling through the first fiber into the protection channels; a first add/drop section for performing adding and/or dropping optical signals passing through the first splitting section to a plurality of channels; a first switching section for combining optical signals in the protection channels to the first fiber when there is no link failure between adjacent nodes and for combining optical signals in the protection channels to the second fiber when there is a link failure between adjacent nodes; and, a controlling section for identifying whether or not the optical link failure occurs in the fibers and for generating a control signal to activate a restoration process according to the identified outcome.

Abstract: An optical multi-ring network for burst data communication is disclosed. The multi-ring network includes a plurality of optical single-ring networks having a plurality of optical add/drop routers connected with each other through fiber links, and a core optical router for supporting communication between the optical single-ring networks. The core optical router includes a wavelength division demultiplexing section for demultiplexing optical signals received from the each single-ring network and outputting the demultiplexed optical signals as channels whose wavelengths are different from each other; a branching section for branching off and outputting a portion of each channel; and a switching section for switching each channel to a path directed to the destination of each channel according to a first control signal.

Abstract: A method for assigning a predetermined wavelength between two different nodes in a wavelength division multiplexing (WDM) ring communication network that has an N number of nodes and at least one pair of optical fibers sequentially connecting the N number of nodes is disclosed. A matrix is formed by an algorithm representing optical-path configuration and wavelength assignment for nodes representing three cases: (1) when the number of nodes is an even number; (2) when the number of nodes is increased; and (3) for recovery from network-cut failures.

Abstract: Disclosed is an optical ring network for burst data communication having a plurality of core nodes connected with each other through fiber links. Each core node comprises a demultiplexer for demultiplexing a received optical signal into a plurality of channels by wavelength, an add/drop section for dropping channels selected from the plurality of channels based on a control signal, a multiplexer for multiplexing and outputting the plurality of channels inputted through the add/drop section, a branching section arranged between the demultiplexer and the add/drop section for branching off channel portions from each channel, and a controller for recognizing destinations for frames with each channel modulated and outputting the control signal for dropping the selected channels to the add/drop section.

Abstract: Disclosed is a wavelength division multiplexing optical switching system, which is connected with a plurality of nodes of an optical network and supports communication between the nodes. The optical switching system includes a wavelength division demultiplexing unit which demultiplexes optical signals received from each of the plurality of nodes and outputs them as channels with different wavelengths. A routing unit which classifies the channels in accordance with destinations thereof. A fixed wavelength converting unit which converts the classified channels into channels of a single wavelength, the single wavelength being allocated in accordance with corresponding starting places. A wavelength division multiplexing unit which collects the wavelength-converted channels in accordance with destinations and then outputs them as multiplexed optical signals.

Abstract: A wideband erbium-doped optical fiber amplifier is disposed among an optical fiber through which a first and second band-band optical signals (for example, the C-band and L-band) are transmitted and forms a first optical path and a second optical path parallel to each other. The wideband erbium-doped optical fiber amplifier comprising a first amplifying section disposed on the first optical path, including a first erbium-doped optical fiber to amplify the first-band optical signals, a filter to gain-flatten the amplified first-band optical signals, wherein a reflected portion of the first band optical signal by the filter is directed to the second optical path; and a second amplifying section disposed on the second optical path, having a second erbium-doped optical fiber to amplify received second-band optical signals, wherein the reflected first-band optical signal is used to pump the second erbium-doped optical fiber.

Abstract: A bidirectional WDM self-healing ring network is provided and includes an outer ring network and an inner network for processing N units of optical signals and for performing a protection switching by using the outer ring network when the inner ring network suffers a link failure.

Abstract: Disclosed is a method, apparatus and computer product for controlling proportional allocation transmission through an OLT scheduling algorithm in an EPON based FTTH system. The method includes computing a total transmission capacity for Optical Network Terminations (ONTs) connected to the OLT, computing a number of transmissions according to the ONTs, storing the computed number of transmissions according to the ONTs in a storage unit, determining a transmission order for each ONT based on the number of transmissions according to the ONTs, and transmitting data according to the determined transmission order.

Abstract: Disclosed is an IP-based broadcast service system capable of reducing the channel zapping or changing time and the waste of bandwidths during frequent channel changes such as channel surfing. A broadcast server for providing broadcast services generates both high-quality broadcast data and low-quality broadcast data of each TV channel. The broadcast server provides the low-quality broadcast data during a simple channel surfing. When a viewer selects a channel to view, the broadcast server then provides the high-quality broadcast data of the selected channel.

Abstract: Apparatus and method for controlling upstream traffic for use in EPON (Ethernet Passive Optical Network) system. The method for controlling upstream data traffic transferred from an ONU (Optical Network Unit) to an OLT (Optical Line Termination) in an EPON (Ethernet Passive Optical Network) system including an ODN (Optical Distribution Network) connected to one OLT, and a plurality of ONUs connected to the ODN and also respectively connected to a plurality of subscribers, includes the steps of a) controlling the OLT to determine an ONU serving as an upstream transmission authority allocation target; b) controlling the OLT to insert information of a predetermined ONU serving as an upstream transmission authority allocation target ONU in a downstream data frame transferred to the ONU, and transmitting the downstream data frame having the inserted ONU information; and, c) controlling the upstream transmission authority allocation target ONU having received the downstream data frame to transmit upstream data.

Abstract: A wideband erbium-doped optical fiber amplifier is disposed among an optical fiber through which a first and second band-band optical signals (for example, the C-band and L-band) are transmitted and forms a first optical path and a second optical path parallel to each other. The wideband erbium-doped optical fiber amplifier comprising a first amplifying section disposed on the first optical path, including a first erbium-doped optical fiber to amplify the first-band optical signals, a filter to gain-flatten the amplified first-band optical signals, wherein a reflected portion of the first band optical signal by the filter is directed to the second optical path; and a second amplifying section disposed on the second optical path, having a second erbium-doped optical fiber to amplify received second-band optical signals, wherein the reflected first-band optical signal is used to pump the second erbium-doped optical fiber.

Abstract: A high speed optical routing apparatus and method, in which data traffic, such as an IP packet, an Ethernet frame, etc., is switched in an optical frame unit at a high speed. The apparatus is provided with a plurality of input and output ports, and with one add port for adding data received from a lower IP router, and one drop port for dropping processed data toward the lower IP router. A header wavelength dividing unit extracts the header wavelength signals from among input optical signals inputted through the input ports and the add port. The header wavelength signals contain header information on data wavelength signals contained in the input optical signals. An optical signal inputting section demultiplexes optical signals having the data signals according to the wavelength, and for dividing and inputting the wavelength-based demultiplexed data wavelength signals according to a frame.

Abstract: Disclosed is an optical ring network for burst data communication having a plurality of core nodes connected with each other through fiber links. Each core node comprises a demultiplexer for demultiplexing a received optical signal into a plurality of channels by wavelength, an add/drop section for dropping channels selected from the plurality of channels based on a control signal, a multiplexer for multiplexing and outputting the plurality of channels inputted through the add/drop section, a branching section arranged between the demultiplexer and the add/drop section for branching off channel portions from each channel, and a controller for recognizing destinations for frames with each channel modulated and outputting the control signal for dropping the selected channels to the add/drop section.

Abstract: A large-capacity optical router is disclosed that exchanges data traffic such as IP packets, Ethernet frames, etc., at high speed in units of optical frames. The large-capacity optical router uses an electric buffer including input ports, output ports, an add port for inputting data received from a lower IP router, a drop port for outputting data to the lower IP router, a wavelength division demultiplexing section for wavelength-division-demultiplexing wavelength signals input through the input ports and the add port, an input interface section for converting optical frames from the wavelength division demultiplexing section into electric signals, and an optical switch for performing a high-speed switching of the optical frames from the input interface section.

Abstract: A bidirectional WDM self-healing ring network is provided and includes an outer ring network and an inner network for processing N units of optical signals and for performing a protection switching by using the outer ring network when the inner ring network suffers a link failure.

Abstract: Disclosed is a two-fiber optical ring network having a plurality of nodes linked by first and second fiber optic links, wherein each node comprises a first splitting section for splitting optical signals from optical signals traveling through the first fiber into the protection channels; a first add/drop section for performing adding and/or dropping optical signals passing through the first splitting section to a plurality of channels; a first switching section for combining optical signals in the protection channels to the first fiber when there is no link failure between adjacent nodes and for combining optical signals in the protection channels to the second fiber when there is a link failure between adjacent nodes; and, a controlling section for identifying whether or not the optical link failure occurs in the fibers and for generating a control signal to activate a restoration process according to the identified outcome.

Abstract: Disclosed is a wavelength division multiplexing optical switching system, which is connected with a plurality of nodes of an optical network and supports communication between the nodes. The optical switching system includes a wavelength division demultiplexing unit which demultiplexes optical signals received from each of the plurality of nodes and outputs them as channels with different wavelengths. A routing unit which classifies the channels in accordance with destinations thereof. A fixed wavelength converting unit which converts the classified channels into channels of a single wavelength, the single wavelength being allocated in accordance with corresponding starting places. A wavelength division multiplexing unit which collects the wavelength-converted channels in accordance with destinations and then outputs them as multiplexed optical signals.

Abstract: An optical multi-ring network for burst data communication is disclosed. The multi-ring network includes a plurality of optical single-ring networks having a plurality of optical add/drop routers connected with each other through fiber links, and a core optical router for supporting communication between the optical single-ring networks. The core optical router includes a wavelength division demultiplexing section for demultiplexing optical signals received from the each single-ring network and outputting the demultiplexed optical signals as channels whose wavelengths are different from each other; a branching section for branching off and outputting a portion of each channel; and a switching section for switching each channel to a path directed to the destination of each channel according to a first control signal.